The present invention relates to a chromatic confocal sensor and a measurement method that uses this.
From the past, a technology of a chromatic confocal sensor has been used for measuring a height of an object to be measured, and the like. For example, Japanese Patent Translation Publication No. 2014/141535 (hereinafter, referred to as Patent Literature 1) discloses a confocal measurement apparatus that performs a multipoint measurement of a displacement of a measurement target using a confocal optical system of a plurality of head portions as shown in FIG. 1 thereof.
In this confocal measurement apparatus, an optical filter is provided in each of the head portions, and a wavelength band to be used for the measurement is set so as to differ among the head portions. For example, in an example shown in FIG. 1 of Patent Literature 1, light having a wavelength of about 400 nm to 600 nm is used in a first head portion 10a, and light having a wavelength of about 600 nm to 800 nm is used in a second head portion 10b (paragraphs [0028], [0031], etc. in specification of Patent Literature 1).
By differentiating the wavelength bands of light to be used in the head portions in this way, an image pickup device arranged inside a spectrometer can be divided into a plurality of areas (channels) to be used by the respective head portions. As a result, a multipoint measurement of a measurement target becomes possible using only one spectrometer (image pickup device) with respect to a plurality of optical heads (paragraphs [0045] to [0049] etc. in specification of Patent Literature 1).